Whip and stub antennas of the type with which we are concerned are relatively small and are capable of shipping in light weight packages. Currently such items are being made abroad in countries where labor is cheap and are being shipped into this country almost with impunity. High frequency whip antennas that are currently commercially available are short whips having a standing wave ratio of 2 to 1 over a band pass of 50 MHZ above and below the design frequency. With the explosion that has occurred in the telecommunication art with cellular telephones, CB'S, ham radios, etc. the channels within a band width have become increasingly crowded, thus making it necessary that the antenna work acceptably well over all the channels in a band. In addition, the competition requires that an antenna manufacturer produce antennas for a number of band frequencies as cheaply as possible to offset the advantage that is had by cheap foreign labor.
An object of the present invention therefore is the production of a high frequency monopole antenna having a standing wave ratio of no more than 2 to 1 over a band width of from approximately 700 MHZ to 1000 MHZ.
Another object of the invention is the provision of a new and improved monopole antenna of the above described type which comprises a minimum of rugged parts whose dimensions can be changed within the envelope of a single injection molding cavity for its housing, to give antennas designed for a number of government specified bands ranging from 120 MHZ to 3000 MHZ.
Another object of the invention is the provision of a new and improved antenna of the above described type which can serve as either a half wave antenna or a quarter wave antenna so that the same size structure can be used effectively for frequencies much lower than possible for a half wave antenna of the same size.
A further object of the invention is the provision of an antenna of the above described type which needs no tuning after it leaves the molding machine in order to center on the design frequency.
Further objects and advantages of the invention will become apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiments described with reference to the accompanying drawings forming a part of this specification.